The news emerges days after CIA experts briefed U.S. Senators about the findings of their investigation, in which they determined Saudi Crown Prince Mohammed bin Salman, of whom Khashoggi was a staunch critic, was heavily involved in the decision to assassinate the newsman.

Penn has yet to comment on the nature of his trip to Turkey, but it isn't the first controversial project he's undertaken - in January, 2016, he hit headlines after documenting his top secret jungle meeting with then-fugitive drug lord Joaquin Guzman, aka El Chapo, at his Mexican hide-out in an article for Rolling Stone magazine. The interview was published a day after Guzman was re-arrested.